Publications

Abstract not provided.

As part of the DOE's multi-laboratory effort to provide analysis and tools to support reconstruction and modernization of the Puerto Rico electric grid, Sandia National Laboratory was tasked with making recommendations for how to use energy storage to support the transmission system. Puerto Rico's electric grid is outdated and still recovering from the 2017 hurricane season, and targeted improvements are needed to restore reliability and to provide resilience for future extreme events. This report examined the most critical near-term issues with the transmission system: frequency regulation and response, and analyzed the impacts of incorporating energy storage systems of varying sizes with the goal of immediately minimizing load shedding while laying the foundation for future renewable energy integration. The analysis concluded that 240 MW/60 MWh of energy storage would stabilize system frequency sufficiently to avoid loss of load for rapid load changes or generation outages up to and including loss of the largest generation unit on the island.

An analysis of microgrids to increase resilience was conducted for the island of Puerto Rico. Critical infrastructure throughout the island was mapped to the key services provided by those sectors to help inform primary and secondary service sources during a major disruption to the electrical grid. Additionally, a resilience metric of burden was developed to quantify community resilience, and a related baseline resilience figure was calculated for the area. To improve resilience, Sandia performed an analysis of where clusters of critical infrastructure are located and used these suggested resilience node locations to create a portfolio of 159 microgrid options throughout Puerto Rico. The team then calculated the impact of these microgrids on the region's ability to provide critical services during an outage, and compared this impact to high-level estimates of cost for each microgrid to generate a set of efficient microgrid portfolios costing in the range of 218-917M dollars. This analysis is a refinement of the analysis delivered on June 01, 2018.

Abstract not provided.

The purpose of this study is to identify potential alternative uses for the LAC-owned BESS. One critical fact that must be considered in evaluating any profitable use of the BESS is the standby cost associated with keeping the NaS battery on-line, as it must be kept at 300 degrees Celsius at all times, regardless of whether it is being used or not. Standby for the NaS battery online requires approximately 80 MWh/month, costing approximately 28,000 dollars annually. Other relevant costs include a 22,000 dollar annual maintenance contract required for the NaS, and accounting for any losses due to inefficiencies during the operation of the battery. County operations personnel respond to all alarms and visit the BESS on a monthly basis to walk down the site. It estimated this cost approximately 10,000 dollars per year. The total cost of maintaining and keeping the NaS battery on-line for a year, then, is roughly 60,000 dollars.